I see. Thank you very much for the images - everything is very clear now.

The same thing has happened to me numerous times. As I mentioned, there are a lot of small "bugs" in the FS X code and this is one of them.

You could, of course, remove the default GPS Hydro file from the directory and create a completely new and accurate file, but that is a very large area to cover and, I think, that it never worked for me. It has been many years since I last tried this, but, if I remember correctly, new GPS Hydro poly files don't display.

Perhaps you could try for yourself and see if that solution will work for you. Good luck.